Airline passengers should not turn on or charge their Samsung Electronics' Galaxy Note 7 smartphones during flights or stow them in checked baggage due to concerns over the phone's fire-prone batteries, the U.S. Federal Aviation Administration said.

In a statement on Thursday, the FAA said it "strongly advises" passengers to follow its guidance "in light of recent incidents and concerns raised by Samsung about its Galaxy Note 7 devices."

The South Korean manufacturer announced last week it was recalling all Galaxy Note 7 smartphones equipped with batteries it has found to be prone to catch fire.

Delta Air Lines, the No.2 U.S. airline by passenger traffic, said it is still studying the issue.

"Delta is in constant contact with the FAA and other bodies in its run of business as a global airline. We will comply with any directive and are studying this matter. Safety and security is always Delta's top priority," spokesman Morgan Durrant said in a statement,

"Each individual carrier makes determinations, in compliance with FAA safety rules and regulations, as to what is permitted to be carried on board and in the cargo hold," Jennings said in a statement.

The FAA statement does not order U.S. airlines to take action.

The International Air Transportation Association said airlines have conducted risk assessments and noted that other phones have been recalled for battery issues.

"Although Samsung is the most recent company advising of faulty devices, others have issued similar recalls and warnings regarding lithium batteries in laptops over the last 12 months, so the industry is familiar with and equipped to manage such situations," the IATA said.

Australian airlines Qantas, Jetstar and Virgin Australia have banned passengers from using or charging the Galaxy Note 7 during flights over fire concerns.

Although customers will still be able to bring the phones on flights on the Australian carriers, the ban extends to the phones being plugged into flight entertainment systems where USB ports are available.